Oliver joseph lodge and lionel lodge



0.1. AND L. LODGE. OBTAINING 0F UNIDIRECTIONAL HIGH TENSION DISCHARGES.

APPLICATION FILED DEC. 13. I913- iatenretl June 24, 1919.

UNITED STATES PATENT oFFIon OLIVER JOSEPH LODGE AND LIONEL LODGE, OF EDGBASTON, BIRMINGHAM, ENGLAND.

OBTAINING OF UNIDIRECTIONAL HIGH-TENSION DISCHARGES.

' have invented new and useful Improvements in the Obtaining of Unidirectional High-Tension Discharges, of which the following is a specification.

Unidirectional high potential discharges such as are required for the operationcnf Ront'gentubes, for dispersing fog, precipitating fume or other small particles, or for stimulating the growth of plants, are com monly obtained either from an alternator connected with a step-up transformer, or from a Ruhmkorif coil. In order that the discharges may be unidirectional itis neces: sary to suppress or reverse one half of each wave of alternating current given by the transformer, and in the ease of an induction coil there is also an inverse E. M. F. on the making of the circuit which requires tobe suppressed or reversed. As a rule the desired eifect is obtained by introducing into the secondary circuit of the transformer or induction coil, a vacuum valve,z'. c. a vacuum tube so designed that current can pass through it freely only in one direction,or a mechanical interrupter or commutator. Either of these devices may be arranged to enable both halves of the alternating current wave to be used. For this purpose in the case of the vacuum valve, four such valves are connected in a. VVheatstone bridge network, with the sourceof supply in the position of the battery, a1id the consuming device in the position of the galvanometer; with interrupter-S a similar eflect is obtained by using two double i n'terrupters, one of which makes connection at the moment when the other breaks, the two, however, making connection iii opposite directions.

A mechanical interrupter does not altogether prevent backward surging'fron the consuming device, while valves become gradually hardened by the repeated application of the inverse E. M. F. which they have to resist.

According to the present invention, therefore, these twodevices are combined, so that the valve may be relieved by the interrupter from the stress of the inverse E. M. F.; and may supplement and be supplemented by the interrupter in stopping backward discharge.

Specification of Letters Patent,

Patented June 24, 1919.

Application filed December 13, 1918. Serial No. 806,600.

For this purpose a mechanical interrupter, which may be rotary or vibratory, and the edect of which is to interpose an air gap or other insulating material or a high resistance into the circuit, is arranged in series with a valve, for instance of the type described in British Patent No. 25047 of 1905.

-The interrupter is driven in s nchronism with the interrupter of the in uction coil or with the alternating current supply as the case may be, so as to break the circuit when the applied E. M. FQchan ges sign or falls below that in the work circuit.

Preferably the interrupter should operate two breaks for each set of valves so as to separate the valves not only from the source of supply but also from the consumlng deviceduring the desired interval.

I If desired the apparatus may be duplicated so as to make use of both the direct and the inverse. waves of current the interrupter being correspondingly modified so as to disconnect the valves which permit current to pass in one direction, while those which permit current to pass in the opposite direction remain in circuit.

The accompanying drawings show diagrammatically how the invention may be put into practice.

' Figure 1 illustrates the invention in a simbe used fordividing the current obtained from the transformer between separate sets of valves, and

Fig. 4: shows an arrangement in which Fig. 3 is so modified as to enable both halves of the wave of alternating current tobe utilized in the D. C. circuit.

In Fig. 1, C indicates an induction c'oil the primary of which is supplied in the usual manner from a battery through an interrupter M, shown as of the rotary type. One terminal of the secondary of the induction coil may be earthed and the other is connected through a mechanical interrupter and valve to a conductor A leading to the high tension apparatus for which a unidirectional 'the interrupter M and is indicated as a conductor R- carried by the shaft S of the interrupter M and adapted twice in a revolution to bridge between the terminals K K, so as substantially to complete a circuit. between them. Y is a vacuum valve connected. in series with this interrupter. The conduo tor It should be so arranged with reference 1 ,is relieved -from withstanding the inverse E. M. Fl.

In the construction of Fig. :2 the interrupter is arranged to produce a double gap so as completely to isolate the valves except when a discharge is passing through them.

The apparatus is indicated as applied to a transformer T the primary of which will receive its current from. an alternating source so that no. interrupter in the primary circuit is needed, The interrupter 1n the secondary circuit consists of an insulating bar upona rotating shaft S carrying two conductorsR R adapted in turn to bridge the gaps between pairs of terminals K, K, and

1;, K, so as twice in a revolution substantlally to complete a circuit through a group, of valves V. Theshaft S must be driven at a rate depending on the frequency of the primary supply, at a half synchronous speed, so thatthe completion of the circuit occurs only at instants of say maximum positive'E. M. F. so that the intervening negative waves of E. M. F. are not applied to the valves at all and the current they 40 would send is wholly suppressed. Moreover the valves are completely isolated even from the work circuit A except about the time of useful discharge, the advantage of this being that if A is maintained at a high potential, the valves have not the strain of this pressure' constantly trying to leak back through them.

The current which the valves can pass without becoming overheated is limited.

With a single set of valves therefore it is.

sometimes impossible to load a transformer or induction coil fully. The current may, however, be distributed between a plurality of sets of valves by the use of a duplicate apparatus such as is'illustrated in Fig. 3. The interrupter shaft S here carries two insulating arms bearing conductors R, R respectively. The conductor R alternately connects the terminals K K and the termina ls K K and the conductor R the terminals K K alternately with the terminals K, K There is a set of valves Y permanently joined between the terminals K K and another set of valves V perma- 65 nently joined between the terminals K K There may be a. conductor R, carried .by the shaft S which bridges between terminals K, K. twice in a revolution. From inspection of the figure it will be seen that the, secondary winding of the transformer T is connected twice in a revolution between the earthed point E and the work circuit A, on one occasion (viz. atthe instant illustrated) through the valves Y, and half a revolution later through the valves v1. The valves which at any instant are not in use are completely isolated, as may be seen from a considerationofvalves V, in the figure. In this construction the shaft S should run at h lf synchronous speed so that alternate positive half waves say, are sent through each set of 'alves, while the negative half waves are suppressed altogether.

, By using a multiple of the revolving switch shown the current may be distributed through a greater-immber of sets ofvalves.

For instance, the structure of Fig. 3 may have four sets of terminals instead of two so that circuits would be con'ipleted'every quarter revolution instead of every half. The shaft S would then be rotated at one quarter a synchronous speedand four sets of valves could be employed, each set taking every fourth positive impulse.

If it is desired to use both the positive and negative half waves of E. M. F. the interrupter of Fig. 3 may be readily modified for this purpose, and one example of this modification is shown in Fig. 4:-

The central spindle S, which in this case has to bedriven at synchronous speed, carries the two insulating bars with conducting end pieces R and R, as before, but the earthing conductor R at the bottom is slightly modified as shown. There are two positions for the device. In that shown one terminal of the secondary of the transformer T, viz.

the bottom terminal, is earthed through contact K and conductor B,- through a slip ring and brush below. The upper terminal of the transformer is connected through contact K conductor R contact K to the set of vacuum valves V and so on to contact K conductor R contact K to the consuming circuit,

In the alternative position of the device after the spindle S has turned through half a revolution the actions are reversed. The upper terminal of transformer T is earthed through contact K and arm as before. The lower terminal is connected through conductor K conductor R contact K to the set of valves V and thence through contact K conductor R contact K to the work circuit. In one position the positive half waves are converted and passed on, and

in the other position the negative half waves are utilized, the two sets of'valves V and V being used alternately.

Alternatively a multiple switch may fulfil both functions of rectifying and of distributing current throughsets of valves. For

instance where there are four sets of valves,

' two sets may take alternate positive im- 6 pulses and the other two sets alternate'negative impulses.

Obviously instead of multiplying the terminals the number of arms carrying conductors could be increased.

It is understood that the systems of.

- connection described illustrate and do not delimit the ve'ntion.

scope of application of the inwwihat we claim is:- a

1' 1. The combination with a source of high electro-motive force and a work circuit adapted to operate atthe upper portion of the current wave, of a vacuum valve, and

valve interposed between said source and said work circuit, and a mechanical interrupter in series with said valve andadapted to interrupt the circuit in two places-one on each side of the vacuum valve.

mechanical means interposed between said,

- 3 The combination with a source of high electromotive force and a ivorl: circuit of a plurality of-vacuumvalves or -sets of vacuum valves, and mechanical lnterrupters 1nterposed between said source and said-work circuit, said interrupters operating to connect said valves or sets of valves in succession between said source and said work circuit during periods of maximum stress and to disconnect the valves during periods of lower stress.

4. In combination, a source of alternating E. M."F.,-a work circuit, sets of vacuum 'valves,'term1nals arranged 1n pairs and connected respectively to said source, said work circuit and said sets of valves, and a rotating shaft carrying a plurality of arms bearing conductors, adapted to connect respective pairs of terminals at one point in their revolution and different pairs ofterminals at another point in their revolutioh so as to join said valves in succession between said source and said work circuit.

Intestirnony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

OLIVER JOSEPH LODGE. LIONFTJ LODGE.

Witnesses NEUCOME TUCKERMAN, ERNEST HARPER. 

